A musical ensemble, also known as a music group, is a group of people who perform instrumental or vocal music, typically known by a distinct name.
In classical music, trios or quartets either blend the sounds of musical instrument families (such as piano, strings, and wind instruments) or group together instruments from the same instrument family, such as string ensembles or wind ensembles.
A string quartet usually consists of two violins, a viola and a cello. An upper string quartet features two violins and two violas. A lower string quartet features one viola, two cellos and a double bass.
In European classical music, piano quartet denotes a chamber music composition for piano and three other instruments, or a musical ensemble comprising such instruments. Those other instruments are usually a string trio consisting of a violin, viola and cello.
A woodwind quartet usually features a flute, an oboe, a clarinet and a bassoon. A brass quartet features two trumpets, a trombone and a tuba. A wind quartet features a horn, a flute, an oboe and a bassoon. A lower wind quartet features a tuba, a bassoon, a bass clarinet and a trombone.
The string quintet is a common type of group. It is similar to the string quartet, but with an additional viola, cello, or more rarely, the addition of a double bass. Terms such as "piano quintet" or "clarinet quintet" frequently refer to a string quartet plus a fifth instrument.
Other common groupings in classical music are the woodwind quintet, usually consisting of flute, oboe, clarinet, bassoon and horn and the brass quintet, consisting of two trumpets, one french horn, a trombone and a tuba.
In jazz, there are several types of trios. One type of jazz trio is formed with a piano player, a bass player and a drummer. Another type of jazz trio is the organ trio, which is composed of a Hammond organ player, a drummer, and a third instrumentalist (either a saxophone player or an electric jazz guitarist). Jazz quartets typically add a wind instrument commonly associated with jazz to one of the jazz trios described above.
Two-member rock and pop bands are relatively rare, because of the difficulty in providing all of the musical elements which are part of the rock or pop sound. The smallest ensemble that is commonly used in rock music is the trio format. In a hard rock or blues-rock band, or heavy metal rock group, a "power trio" format is often used, which consists of an electric guitar player, an electric bass guitar player and a drummer, and typically one or more of these musicians also sing. The four-piece band is the most common configuration in rock and pop music. Before the development of the electronic keyboard, the configuration was typically two guitarists (one lead guitarist and one rhythm guitarist, with the latter on vocals), a bassist (typically the electric bass guitar) and a drummer.
Five-piece bands have existed in rock music since early times.
A small orchestra with fifteen to thirty members (violins, violas, four cellos, two or three double basses, and several woodwind or brass instruments) is called a chamber orchestra. A sinfonietta usually denotes a somewhat smaller orchestra (though still not a chamber orchestra). Larger orchestras are called symphony orchestras (see below) or philharmonic orchestras.
A concert band, also called wind band, symphonic band, symphonic winds, wind orchestra, wind symphony, wind ensemble, or symphonic wind ensemble, is a performing ensemble consisting of several members of the woodwind, brass, and percussion families of instruments.
A pops orchestra is an orchestra that mainly performs light classical music (often in abbreviated, simplified arrangements) and orchestral arrangements and medleys of popular jazz, music theater, or pop music songs. A string orchestra has only string instruments, i.e., violins, violas, cellos and double basses.
A symphony orchestra is an ensemble usually comprising at least thirty musicians; the number of players is typically between seventy and ninety-five and may exceed one hundred. A symphony orchestra is divided into families of instruments. In the string family, there are sections of violins (I and II), violas, cellos (often eight), and basses (often from six to eight). The winds consist of the woodwind family of instruments (flutes and piccolo, oboes and English horn, clarinets [made up of the E♭ clarinet, clarinet, and bass clarinet], saxophones, and bassoons [often including contrabassoon]) and the brass family (horns, trumpets, trombones, euphonium, baritone horn, and tuba). The percussion family includes the timpani, bass drum, snare drum, and any other percussion instruments called for in a score (e.g., triangle, glockenspiel, chimes, cymbals, wood blocks).